Telescopic catheters are commonly used to provide additional degrees of freedom to a catheter system for traversing complicated, tortuous, unsupported, and/or other challenging anatomy. While these generally work well, it can be cumbersome to keep track of the relative positions of the catheter elements, especially in systems where a highly flexible inner telescoping element is desired and/or relative positions of telescoping elements must remain finely indexed at the tip. These problems are exacerbated in conditions where a third or fourth inner telescoping element is desired. While position and locking mechanisms are common on the “back” end of these catheters, these elements are frequently insufficient to keep the “tips” of telescoping catheter elements aligned as desired. This is because the flexible, bendable nature of catheters causes path length changes in the catheters themselves, which render proximal end based alignment problematic/insufficient.
Therefore, apparatus and methods that facilitate use of such telescoping catheters would be useful.